ARM: dts: lpc18xx: add EEPROM memory node

Add node for the NXP LPC18xx EEPROM memory which can be found in
NXP LPC185x/3x and LPC435x/3x/2x/1x devices.

Signed-off-by: Ariel D'Alessandro <ariel@vanguardiasur.com.ar>
Signed-off-by: Joachim Eastwood <manabian@gmail.com>